User blog comment:Ashleegreninja/Was this a bad trade?/@comment-32092633-20180416232603

Bottle Cap is definitely rare.

Shiny Dunsparce, eh.

Remember, Bottle Caps can only be obtained with a perfect five digits, and Dunsparce is kind of useless.

So... Bottle Cap is rarer as it could have gotten Hidden Ability PvP Pokemon.